<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>后盾人 - houdunren.com</title>
  </head>
  <body>
    <div id="app">
      <div class="houdunren" data="hd">houdunren.com</div>
      <div class="houdunwang">
        houdunwang.com
        <span>向军</span>
      </div>
      <div class="xiangjun"><!-- 向军大叔 --></div>
    </div>

    <script>
      const app = document.querySelector('#app')
      //   console.log(app)
      console.log(app.children)
      console.log(app.firstElementChild)
      console.log(app.lastElementChild)
      console.log(app.parentElement.parentElement.parentNode)

      const houdunwang = document.querySelector('.houdunwang')
      console.log(houdunwang.nextElementSibling)
    </script>
  </body>
</html>
